Slowly but surely this app breaks down more and more and I try to find solutions but it seems like no one is using it or no one cares. Numerous integrations that used to work just fine have stopped working and the app itself runs worse than it did. Things that have been issues since the very beginning of the apps release have not even been touched on by developers. Extremely simple feature requests or bug fixes are all ignored for literal years on end.

I wanted so badly to replace every other launcher besides Steam and GoG, and now those seem to be the only integrations this app is able to launch reliably *and* my app is filled to the brim with irremovable ROM games from my unsuccessful attempt to bring those in before I found Launchbox (I've spent like 6 hours trying to remove the integrations that don't even exist). It's far worse now than using any of the individual launchers would be because I'm constantly battling with integrations disconnecting and now I must sort through thousands of titles I don't want in my list because there's no way to remove these ROMs aside from hiding them one by one which would take weeks.

to remove an integration, disconnect it and delete it's folder from "%LOCALAPPDATA%\GOG.com\Galaxy\plugins\installed", then just restart the client

I'm afraid it's not that simple. I've done that and MUCH much more.

Also this doesn't even work for normal things like it should. When I restart Galaxy it adds Bethesda all by itself for instance. I delete the folder in the location you have listed here and it pops right back up when I open Galaxy. So somewhere is a list telling it what plugins to re-download when needed on top of that. As for the ROMs I have no integration files that can be found ANYWHERE in relation to them. They are baked into some python script or something somewhere that I cannot find. I have read all sorts of threads and I know you didn't mean to be offend, but that was advice I read several dozen attempts ago and it wasn't going to help then.

EDIT:
One issue solved, I had to remove Bethesda from
ProgramData\GOG.com\Galaxy\storage\plugins
as well to prevent it from restoring itself.

Strange, I don't have a plugins folder in that location

I kind of agree. Once in a while they add a new feature instead of making the app faster and more reliable. And some integrations haven´t been updated in a while (the Ubisoft Connect one is the worst).

I don't directly blame the devs for integrations not working as they are mostly community made, but I do blame them for not making any themselves after this many years since I thought it was kind of the point of Galaxy 2.0 to replace the need for a million launchers, and I do blame them the fact that the integrations don't seem to have much in terms of standardization that protect users and improve the experience. The app I used to get my ROMs into Galaxy found here seems to have really f*cked it all up for me and the devs haven't done anything to make it easy to remove games in bulk that you do not want in Galaxy:
https://github.com/jshackles/RetroGOG

I have removed the integrations but the games remain listed.

Official integrations are not updated frequently either. For example, Epic Games Store has support for achievements, but they don´t show up in Galaxy. The app has other issues that have not been addressed, such as long startup time if you have a large library of games. It also feels sluggish when scrolling your library, and sometimes the app just freezes briefly. I guess they don´t have the resources to support the app more often, and that´s why it has not improved that much after years of being released. The idea is fantastic, but the execution could be better.